Dysphagia is the medical term for the symptom of difficulty in swallowing. Current evidence suggests that 22% of adults over the age of 50 years, and most adults by age 80 years, experience swallowing difficulty. Oral nutrition is the desirable goal for every dysphagic patient, but in some cases may not be possible or appropriate. If adequate nutrition cannot be achieved, or if aspiration of material into the lungs cannot be prevented, non-oral feeding may need to be implemented. This alternative, however, is both costly and unsatisfying to many individuals.
Therefore, strategies designed to improve swallowing safety and effectiveness in at-risk patients are commonly sought by clinicians working with dysphagic individuals. One well-known and frequently implemented technique involves the manipulation of bolus consistency. This is particularly considered when patients demonstrate difficulty with thin liquid bolus materials, e.g. water. Nutritional feeds are thickened to a safe and effective consistency based on results of clinical and instrumental assessments. In 2002, the American Dietetic Association established guidelines for thickened dietary supplements. Proposed in the Dysphagia Diet were viscosity ranges for thin (1-50 cP), nectar (51-350 cP)-like and honey-like (351-1750 cP) liquids.
Many of the currently available thickening products are based on starch, which does not dissolve well in some liquid products, tastes “starchy” and can form lumps over time. If patients find these products aversive, they are unlikely to consume them, thus precluding their potential value in optimizing swallow safety. In addition, if the stability of the consistency is in question, clinicians have difficulty recommending the product. Recently, gel thickeners have become available that are not associated with a bad taste, don't change the color of the liquid they're added to, and don't form lumps. In addition, they are purported to reach target viscosity rapidly, making them better suited to heated products, such as coffee or tea. The better texture and taste are due to the use of xanthan gum rather than starch. One such product is Resource® ThickenUp Clear. The gum-thickening agent was developed to improve solubility, viscosity and taste, as compared to currently available products.
However, although potential benefits of commercial gum-based products in altering bolus rheology are recognized, there have been few systematic efforts to alter bolus rheology in consideration of the type of aspiration relative to the swallowing reflex.
The inventors have found that treating dysphagic patients with standard boluses having increased viscosity such as nectar-like liquids may not only be ineffective with regard to improving swallowing function. For some patient groups, such standard bolus therapy is even likely to cause adverse effects and to increase aspiration prevalence. For example, thickened liquid boluses having a high shear viscosity were found to be beneficial in patients aspirating before and during swallowing. However, the same bolus was found to be detrimental for patients who tend to aspirate after the swallowing reflex.
Considering the prevalence of dysphagia, possible complications related thereto, and the costs associated with same, there is still a need for providing an improved method for treating swallowing disorders, which method can minimize the risk of standard bolus therapy and promotes safer swallowing of food boluses in patients suffering from aspiration. Such a method would improve the lives of a large and growing number of persons with swallowing impairments. Specific interventions (e.g., to promote oral health, help restore normal swallow, or reinforce a swallow-safe bolus) can enable persons to eat orally (vs. being tube fed and/or requiring PEG placement) and experience the psycho-social aspects of food associated with general well being while guarding against the potentially negative consequences that result from lack of adequate swallowing ability. Improvements in the intake of nutrition by dysphagic patients may also enable such patients to swallow a wider variety of food and beverage products safely and comfortably, which may lead to an overall healthier condition of the patient and prevent further health-related decline.